Research on Optimization of Bolt Support for Tilted Strata Roadway in Soft Rock

2014 ◽  
Vol 962-965 ◽  
pp. 379-383
Author(s):  
Liang Tian ◽  
Shao Peng Jiao ◽  
Wen Feng Zhao ◽  
Xian Yong Hao ◽  
Cheng Cheng
Keyword(s):  
Failure Mechanism ◽  
Stress Measurement ◽  
Soft Rock ◽  
Tectonic Stress ◽  
Tensile Failure ◽  
Rock Stress ◽  
Support Design ◽  
Original Rock ◽  
Roadway Deformation ◽  
Support Methods

Bad and asymmetrical deformation occurred in soft tilted strata roadway for the existence of tectonic stress, we carried out the study on geostatic stress character and optimizing bolting support parameters in 2# coalbed of Zijin Colliery. Based on original rock stress measurement, broken rock zone measurement and survey of roadway deformation, characters of original rock stress and range of broken rock zone were given. According to existent problems, a variety of numerical computations were carried out by FLAC3D, failure mechanism of roof is shear-tensile failure. New support methods of bolt installed vertically in tilted roof and strengthening support of sidewalls and corners of roadway are figured out. The research was carried out for 600 meters. The monitoring results prove that the optimized support design is viable and the new bolting parameters are reasonable.

Research on Geostatic Stress and Optimization of Bolt Support for Tilted Strata Roadway

2014 ◽  
Vol 580-583 ◽  
pp. 1335-1341 ◽  
Author(s):  
Ren Liang Shan ◽  
Liang Tian ◽  
Wen Feng Zhao ◽  
Jin Yang Lv ◽  
Yu Hang Xiao ◽  
...  
Keyword(s):  
Rock Stress ◽  
Numerical Computations ◽  
Support Design ◽  
Geological Conditions ◽  
Measurement And Analysis ◽  
Original Rock ◽  
Roadway Deformation ◽  
Support Methods ◽  
Bolt Support

In order to tunnel safely, efficiently and economically, we carried out the study on geostatic stress characters and optimizing bolting support parameters in 2# coalbed of Zijin Colliery. Based on the surveys of geological conditions, original rock stress, broken rock zone measurement and analysis of roadway deformation, characters and mechanism of roadway failure is figured out. According to existent problems, normal support theories were used and a variety of numerical computations were carried out by FLAC3D.New support methods of bolt installed vertically in tilted roof and strengthen support of sidewalls and corners of roadway were figured out. Monitoring of convergence meters and roof separation were followed to know effects of new design timely. The research was carried out for 600 meters The monitoring results proved that the optimized support design was viable and the new bolting parameters were reasonable.

Geo-Stress Measurement and its Application in the Yangchangwan Coal Mine

2013 ◽  
Vol 353-356 ◽  
pp. 398-402
Author(s):  
Xiao Yu Zhang ◽  
Feng Ming Liu ◽  
Gang Chen
Keyword(s):  
Stability Analysis ◽  
Coal Mine ◽  
Basic Parameter ◽  
Stress Measurement ◽  
Three Dimensional ◽  
Stress Relief ◽  
Tectonic Stress ◽  
Surrounding Rock ◽  
Support Design ◽  
Rock Stability

The initial stress of rock is a basic parameter, which can be used for surrounding rock stability analysis, exploitation and support design. By utilizing stress relief method of hollow inclusion with its characters of high precision and obtaining three dimensional stress at one time, we have measured three dimensional stress magnitude and direction in north wing roadway (-850m) and 710 open-off cut (-1000m), respectively. The results show that the horizontal tectonic stress is obvious in this coal area.

scholarly journals Failure Mechanism Analysis and Support Design for Deep Composite Soft Rock Roadway: A Case Study of the Yangcheng Coal Mine in China

2015 ◽  
Vol 2015 ◽  
pp. 1-14 ◽  
Author(s):  
Bangyou Jiang ◽  
Lianguo Wang ◽  
Yinlong Lu ◽  
Shitan Gu ◽  
Xiaokang Sun
Keyword(s):  
Failure Mechanism ◽  
Coal Mine ◽  
Failure Mechanisms ◽  
Soft Rock ◽  
Deformation Monitoring ◽  
Surrounding Rock ◽  
Support Design ◽  
Soft Rock Roadway ◽  
Rock Roadway

This paper presented a case study of the failure mechanisms and support design for deep composite soft rock roadway in the Yangcheng Coal Mine of China. Many experiments and field tests were performed to reveal the failure mechanisms of the roadway. It was found that the surrounding rock of the roadway was HJS complex soft rock that was characterized by poor rock quality, widespread development of joint fissures, and an unstable creep property. The major horizontal stress, which was almost perpendicular to the roadway, was 1.59 times larger than the vertical stress. The weak surrounding rock and high tectonic stress were the main internal causes of roadway instabilities, and the inadequate support was the external cause. Based on the failure mechanism, a new support design was proposed that consisted of bolting, cable, metal mesh, shotcrete, and grouting. A field experiment using the new design was performed in a roadway section approximately 100 m long. Detailed deformation monitoring was conducted in the experimental roadway sections and sections of the previous roadway. The monitoring results showed that deformations of the roadway with the new support design were reduced by 85–90% compared with those of the old design. This successful case provides an important reference for similar soft rock roadway projects.

scholarly journals Load transfer mechanism and reinforcement effect of segmentally yieldable anchorage in weakly consolidated soft rock

SIMULATION ◽  
2018 ◽  
Vol 95 (1) ◽  
pp. 83-96 ◽  
Author(s):  
Zenghui Zhao ◽  
Qing Ma ◽  
Yunliang Tan ◽  
Xiaojie Gao
Keyword(s):  
Load Transfer ◽  
Tensile Deformation ◽  
Numerical Models ◽  
Soft Rock ◽  
Surrounding Rock ◽  
Tensile Failure ◽  
Western China ◽  
Support Design ◽  
Pull Out ◽  
Roof Fall

Mine disasters, such as large deformation, floor heave, and roof fall, occur extremely easily in weakly consolidated soft rock strata in western China, posing enormous challenges to traditional anchorage support design. To avoid tensile failure of bolts as a result of the superposition effect of stress accumulation, a segmentally yieldable anchorage support, taking into consideration the different failure zones in surrounding rock, is presented in this paper. First, load transfer mechanisms and the process of anchorage failure are analyzed for end anchorage, full-length anchorage, and segmentally yieldable anchorage based on numerical pull-out tests. Results show that the load transfer follows a multipeak chain-like trend in the case of multipoint segmental anchorage, and that the peaks of stress attenuate slowly. Therefore, the proposed anchorage type can leverage the shear strength effectively. Furthermore, numerical models for the applications of the aforementioned three different anchoring modes to weakly consolidated soft strata are established. Results indicate that segmentally yieldable anchorage can withstand larger tensile deformation and surrounding rock deformation. Moreover, the bolt shows higher strength reservation. A combination of these characteristics is conducive to controlling deformation and damage during roadway excavation.

scholarly journals A Case Study on Large Deformation Failure Mechanism and Control Techniques for Soft Rock Roadways in Tectonic Stress Areas

2019 ◽  
Vol 11 (13) ◽  
pp. 3510 ◽  
Author(s):  
Xue ◽  
Gu ◽  
Fang ◽  
Wei
Keyword(s):  
Numerical Simulation ◽  
Large Deformation ◽  
Failure Mechanism ◽  
Support System ◽  
Soft Rock ◽  
Tectonic Stress ◽  
Geological Conditions ◽  
Soft Rock Roadway ◽  
Rock Roadway

Large deformation and failure of soft rock are pressing problems in the mining practice. This paper provides a case study on failure mechanisms and support approaches for a water-rich soft rock roadway in tectonic stress areas of the Wangzhuang coal mine, China. Mechanic properties of rock mass related to the roadway are calibrated via a geological strength index method (GSI), based on which a corresponding numerical simulation model is established in the Universal Discrete Element Code (UDEC) software. The failure mechanism of the roadway under water-saturating and weathering conditions is revealed by field tests and numerical simulation. It is found that the stress evolution and crack development are affected by weathering and horizontal tectonic stresses. The roadway roof and floor suffer from high stress concentration and continuous cracking, and are consequently seen with rock failure, strength weakening, and pressure relief. Unfortunately, the current support system fails to restrain rock weathering and strength weakening, and the roadway is found with serious floor heave, roof subsidence, and large asymmetric deformation. Accordingly, a new combined support system of “bolt–cable–mesh–shotcrete + grouting” is proposed. Moreover, numerical simulation and field testing are conducted to validate the feasibility and effectiveness of the proposed approach, the results of which demonstrate the capacity of the proposed new support method to perfectly control the surrounding rock. Findings of this research can provide valuable references for support engineering in the soft rock roadway under analogous geological conditions.

scholarly journals Research on Full-Section Anchor Cable and C-Shaped Tube Support System of Deep Layer Roadway

Geofluids ◽  
2021 ◽  
Vol 2021 ◽  
pp. 1-13
Author(s):  
Renliang Shan ◽  
Shupeng Zhang ◽  
Pengcheng Huang ◽  
Weijun Liu
Keyword(s):  
Support System ◽  
Surface Displacement ◽  
Field Tests ◽  
Soft Rock ◽  
Shear Resistance ◽  
Tectonic Stress ◽  
Anchor Cable ◽  
Shaped Tube ◽  
Roadway Deformation ◽  
Prestressed Anchor

Deep roadway deformation due to soft rock, rock dip, and horizontal tectonic stress is uneven and asymmetrical primarily in large loose zones. Traditional anchor support is influenced by the yield strength and shear strength of the anchors and has a limited prestress capacity or shear resistance. When the roadway roof is laminated rock or when the roadway passes through layered rock or rock interfaces, interlayer sliding commonly occurs, which can easily lead to anchor cables being sheared off. The tape tunnel in the Zhengling Mine passes through several rock strata and requires anchors to achieve a high shear resistance and prestress. To solve these problems, an anchor cable and C-shaped tube that can bear lateral shear forces were developed, and a full-section anchor cable and C-shaped tube support system were created based on extruded arch theory. Numerical results from FLAC3D show that the new scheme effectively controls surface convergence and plastic zone extension. Field tests have demonstrated that the amount of surface displacement was at least 42% smaller in the new support scheme. The extruded arch formed by the highly prestressed anchor cable and concrete spray layer can effectively control the bulking load within the loose zone, and the ACC effectively resists interlayer shear.

Analysis of Combined Support Technology with U-Shaped Steel Bracket and Anchor Bolt

2013 ◽  
Vol 345 ◽  
pp. 238-242
Author(s):  
Hai Long Dong ◽  
Peng Wei Hao ◽  
Zhao Hui Liu ◽  
Jing Pei Li ◽  
Lai Wang Jing
Keyword(s):  
Soft Rock ◽  
Support Effect ◽  
Curved Beam ◽  
Anchor Plate ◽  
Support Design ◽  
Anchor Bolt ◽  
Roadway Support ◽  
Channel Beam ◽  
Support Methods ◽  
Bolt Support

This paper synthetically analyzed essential features of various support methods in engineering geological soft rock, proposed a scheme that organically combines active support (like anchor bolt support) with passive support (like U-shaped steel bracket support), analyzed fundamentals of this combined support scheme, and forecasted support effect of this support scheme. It provides roadway support design with fresh ideas. U-shaped steel bracket can be translated into special anchor plate with the help of a section of simple steel channel beam, so effect of anchor bolt can be ensured; U-shaped steel bracket , this extremely long curved beam ,will be divided into several sections of short beams, so its bearing ability will be several times improved. Cost of this combined support scheme is low, its process is simple and its application prospect is wide.

scholarly journals Study on the Mechanical Behavior of Double Primary Support of Soft Rock Tunnel under High Ground Stresses and Large Deformation

2020 ◽  
Vol 2020 ◽  
pp. 1-9
Author(s):  
Zhe Liu
Keyword(s):  
Mechanical Behavior ◽  
Large Deformation ◽  
Design Method ◽  
Characteristic Curve ◽  
Soft Rock ◽  
Support Design ◽  
Deformation Amount ◽  
Secondary Lining ◽  
Rock Tunnels ◽  
Primary Support

Double primary support structures could effectively solve the problem of large deformation of surrounding rock for soft rock tunnels. However, the mechanical behavior of this new support structure is still incomplete, and the design method should be revised. Based on the theory of energy conversion, this paper analyzes the support characteristic curve of double primary support and puts forward the dynamic design method of double primary support. Considering that the secondary lining can be set after monitoring the deformation amount and deformation rate of the first primary support, its support parameters can be dynamically adjusted according to the actual situation. By applying the double primary support design method in the Maoxian tunnel of Chenglan Railway, the field monitoring results show that the double primary support has a significant effect on the energy release of surrounding rocks, greatly reducing the load acting on the secondary lining and ensuring the safety and reliability of the tunnel structure.

Roadway deformation during riding mining in soft rock

2012 ◽  
Vol 22 (4) ◽  
pp. 539-544 ◽  
Author(s):  
Guozhen Zhao ◽  
Zhanguo Ma ◽  
Qinghua Zhu ◽  
Xianbiao Mao ◽  
Meimei Feng
Keyword(s):  
Soft Rock ◽  
Roadway Deformation
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